536 
I am firmly of the belief that had Dr. Dean made his drawings 
from the living egg and confirmed their correctness by the study of 
material fixed by a number of reagents, our results would have been 
in complete agreement. This conviction is supported by the appearance 
of the marginal grooves shown in Dran’s figures 8, 11, Pl. I, and 
further strengthened by a suggestion in a foot note (p. 18) which reads 
as follows: “The writer has found no segmentation stages in which 
the furrows extend much lower than the equatorial region of the egg. 
He does not, accordingly, confirm the note and figure of BALFOUR, 
and is inclined to believe that the total segmentation of Lepidosteus 
occurs only as a variation”. 
It would thus appear that the differences of opinion expressed 
by BALFOUR and PARKER, DEAN and myself might possibly be explained, 
but to reconcile these with the view of Brarp is impossible. The 
only conclusion is that either the observations, somewhere, embody 
most extraordinary errors or that the cleavage of the egg of Lepidosteus 
is of a heterogeneous character — a discovery of no little theoretical » 
import. Which of these alternatives shall be accepted must depend 
upon later investigation. 
Hull Anatomical Laboratory, Aug 25, 1899. 
Nachdruck verboten. 
The Regeneration of a Head instead of a Tail in an Earthworm. 
By Annan Purnam Hazen. 
With 6 Figures. 
It has been shown by SPALLANZANI, MoraGan, and HESCHELER that 
a short piece cut from the anterior end of an earthworm dies with- 
out regenerating the posterior end, although such a piece often lives 
for several weeks or even months. It is not known, however, whether, 
if such pieces could be kept alive for a longer time, they would regener- 
ate, or whether, if regeneration did occur, a head or a tail would 
develop. 
By grafting, in a reversed direction, the small anterior end of 
one worm upon a large posterior piece of another worm, the small 
piece can be kept alive for a much longer time. Under these circum- 
stances, I hoped to be able to determine’ whether a head or a tail 
would develop from the free (posterior) end of the small graft. 
